On-site construction of a house may be prohibitively costly in terms of labor, materials, and time. Accordingly, much effort has been expended to develop prefabricated modules for expedited building construction. These methods have also attempted to maintain the ambiance and character desired by the buyer. Known methods include the construction of entire portions of houses at a remote manufacturing facility. The pre-constructed units are then shipped to the building site and finally assembled in building block fashion.
An example of a conventional construction method is disclosed in U.S. Pat. No. 4,501,098 to Gregory. A portion of a house is constructed off-site in a factory and remaining portions of the house are constructed on-site.
More specifically, a module of the house can be built off-site, transported to the building site, and positioned on a foundation to substantially form a "first level" of the house. Thus, those portions of the house that are "nonexpressive", i.e., which have standard features from floor surface to ceiling, are modularly constructed. The remaining portions of the house are constructed on-site to create enlarged living space areas.
The pre-constructed modules are placed on a foundation, which includes a slab that serves as a floor surface for house portions built on-site. However, the transportation and construction of the modules required non-standardized trailers to accommodate the various types of modules. Since portions must still be custom-constructed on-site, this technique does not substantially reduce the cost of constructing houses or the amount of time required.
The another example is U.S. Pat. No. 4,485,608 to Kaufman, et al. This patent discloses a prefabricated self-contained building and construction method for transporting and lifting building structures in their entirety without the need for providing floors. This is accomplished by fully constructing a floorless building that is lowered by a crane system 21 into position on a slab foundation 23. The slab foundation becomes the floor once the building is placed thereon (see column 4, lines 13-16). However, the transport of a building in its entirety requires a heavy weight trailer, and the load may not conform to VDOT (Vehicle Department of Transportation) size limits 14'.times.14'.times.95'. Moreover, a heavy crane is needed to lift the structure in order to load it onto the trailer and lower it onto the foundation. Further, prefabricating a whole building structure off-site, in its entirety, may not have a cost advantage over constructing a whole building at the building site.
Evans et al., U.S. Pat. No. 3,716,112, discloses a steel modular building arranged in a J-plan. According to Evans, a bedroom module, a utility core module, and a living room module are prefabricated in a factory or the like. The module includes a steel frame construction. Each module is made by constructing wall, floor, and roof frames, assembling the frames into a module, and welding the frames together. The prefabricated modules are then transported to the home site. Since Evans includes the roof frames, transportation of the modules requires a heavy weight trailer, and the load may not conform to the VDOT size limits. In addition, Evans discloses moving the modules between spaced apart building stations in the factory. Such movement between stations requires heavy equipment and wastes time.
U.S. Pat. No. 4,513,545 to Hopkins, Jr. also discloses modular structures. Hopkins discloses a structure that is formed by stacking modules. Hopkins discloses apparatus and method for constructing two-story dwellings or offices in which "core modules" are prefabricated and transported to a site and a remainder of the dwelling is completed using additional "wall elements" and other on-site labor techniques. Thus, Hopkins requires extensive on-site labor. U.S. Pat. No. 4,003,182 to Wokus discloses a method of building construction wherein factory built room forming boxes are set in place on a foundation. After the boxes are set in place, the structure is built up around the boxes using the boxes as a core. Thus, the Wokus method requires extensive on-site labor. U.S. Pat. No. 5,353,453 to Leslie discloses a rapidly erectable housing unit. Each unit is constructed from non-uniform wall sections and roof sections. The wall sections and roof sections are joined on-site to form the basic structure. Thus, Leslie, like Hopkins and Wokus, requires extensive on-site labor.
U.S. Pat. No. 2,604,060 to Hanson discloses a roof structure for use with prefabricated houses. Hanson's prefabricated roof structure folds into a compact package for transportation to a construction site. Once at the construction site, the structure is unfolded and connected to several other similar structures to form a roof. Like Hopkins, Wokus, and Leslie, Hanson's roof structure requires substantial on-site labor.